Note 3 - Goodwill and Other Purchased Intangible Assets - Purchased Intangible Assets, Subject to Amortization (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 26, 2015	Dec. 27, 2014
Rasco Technology [Member]
Intangible assets, gross	$ 27,435	$ 29,845
Intangible assets, accumulated amortization	$ 23,388	22,616
Intangible assets, useful life	1 year 109 days
Ismeca Technology [Member]
Intangible assets, gross	$ 27,248	27,014
Intangible assets, accumulated amortization	$ 9,540	6,879
Intangible assets, useful life	5 years 109 days
Intangible assets, gross	$ 54,683	56,859
Intangible assets, accumulated amortization	$ 32,928	$ 29,495